Overproduction of a Clostridium cellulolyticum endoglucanase by mutant strains of Escherichia coli

We have studied the expression of an endoglucanase from Clostridium cellulolyticum in mutant strains of Escherichia coli that overproduce haemolysin. When these mutants were transformed with plasmids encoding the endoglucanase, they showed a significantly enhanced endoglucanase activity, compared to transformed parental strains. Among the mutants, strain Hha-2 showed the highest production. We have identified the endoglucanase gene product synthesized in E. coli Hha-2/pBP8 and detected an increased amount of the enzyme parallel to the increase of endoglucanase activity. This was mainly localized in the periplasm and only a small percentage of it was found in the culture fluid.